There are two main problems in current LED lighting market:
The first one: unclear identity. According to the test of ITRI industry, more than 50% LED bulbs in the market are insufficient in output luminous flux as they have been marked. It is estimated that measured results will be 10% less than the value given out by laboratory experiments.
The second problem is the different quality. Currently, there is no unified standard to provide clear definitions to the relationship between prices and qualities. In most of cases, customers might spend a lot of money but did not obtain the corresponding high-quality products. This situation made buyers from other regions, like Europe and the United States paid more attention on the identity and quality of LED lamps/bulbs.
Does the lumen maintenance data can represent the service life of LED lamps? At present, the most official representative standard related to the service life of LED bulbs in the LED lighting market should be the LM-80 specification released by the Energy Star (U.S. Environmental Protection Agency) for LED Lamps. However, a number of different voices now have been found in North America. Some experts call on the abolishing of LM-80 specification immediately since it is not accurate as people expected in estimating the service life of LED bulbs. At least, it should not be the only specification for that.
In fact, in 2006, the U.S. Department of Energy Quality Working Group for Solid State Lighting (SSL) invited 32 LED experts and conducted a series of deep discussions about the reliability and lifetime estimation methods for LED lighting products. In consideration of the LED technologies at that moment, it is proved that lumen maintenance (L70) will be the most representative and most reliable specification for determining the life time of LED lamps. The light attenuation of LED lights is step by step process, which is too slow to be sensed by human. In the early stage of light attenuation, people can hardly recognize their lamps become dimmer. Not until the light attenuate to only 70% of the initial light intensity, the lost brightness of LED lights can be noticed. Thus the working group of U.S. Department of Energy Quality Working Group for Solid State Lighting suggested that L70 should be the only standard of LM-80 specification in determining the lifetime of LED lights, including LED bulbs.